package com.design;

/**
 * 内部内（线程安全）
 */
public class Singleton04 {
    /**
     * 内部类
     */
    private static class Singleton04Internal{
        private static final Singleton04 singleton04 = new Singleton04();
    }

    public static Singleton04 getSingleton04(){
        return Singleton04Internal.singleton04;
    }
    private Singleton04(){

    }
}
